Communication system



April 24, 1945- w. M. BACON ETAL COMMUNICATION SYSTEM Filed Aug. 26, 1942 SheebS-Sheet l D n A 4 E w, X MA m CED Mam ./K f Mkw wsxw ESM h mm. O M W M s Si G m ww w @Q 59k QNN NNN @NN bym Qlyl. D

ATT ORNE V April 24, 1945. W M, BACON ET AL 2,374,264' I" COMMUN I CATI ON SYS TEM Filed Aug. 26, 1942 6 Sheets-Sheet 2 NON /NVENTORSFW R/m s. /r/NKEAD Hfs AoM/N/STRA rR/x Trop/vw w. M. BACON ETAL 2,374,264

COMMUNICATION SYSTEM Filed Aug. 26, 1942 6 Sheets-Sheet 5 ESJINKEAQDECEASED April 24, 1945.

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' Arron/vn 6 Sheets-Sheet 4 -W. M BACON ET AL COMMUNICATION SYSTEM Filed Aug. 26, 194

pril 24, 1945.

April 24, 1945. w. M. BACON ETAL COMMUNICATION SYSTEM Filed Aug. 26, 1942 6 Sheets-Sheet 5 ME si E zolou F5 K/NKEDECESED By a.. fw.

Arroma'r April 24, 1945. w. M. BACON ET AL 2,374,264

COMMUNICATION SYSTEM Filed Aug. 26, 1942 e sheets-sheet e TRANS DIS TR/H RE C 'G REPERF TA PE 725 URIGMM TING STA TION A T TORNE' Y Patented Apr. 24, 1945 CGMMUNICATION SYSTEM .'-Walter M.,Bacon, New York, N. Y., and Fullerton S..Kinkead, deceased, late of `New York, N. Y.,

`byRitaSmith Kinkead,.administratrix, New

i York, N. Y., .assgnors to Bell Telephone Laboratores, Incorporated, New York, N. Y., a corporation of New York Applicatibnaugust 26,1942; serial N0.456,146

x vide a special `.arrangement intermediate:I the vr`i;transmitter.andy the 'receiver' for automatically causing the transmission ,oi predetermined sishals fOr-:causing the tape `to be advanced throughl 13 Claims.

1 l Thisv inventionf relates vto communication systems and more particularly:to .telegraph systems which received Vtelegraph signals are recorded `by a receiving instrument. l .It fis :frequently desirable lin systems wherein telegraph A'signals or messagesy are Vrecorded by the recording: instrument when therecording in- 1 strument remainsidle for :a predetermined-short telegraph Areceiving"instruments to cause the .-smedium-upon Whic'hfthe `signals are recorded to beiautomatically` advanced out of the recording Y instrument at the end of the-message or at the `end oa grou-p of signals characterized-by any distinguishingcharacteristics.

In case itis-desired to` receive telegraph signals uponreperforating instruments-or a printingfreperforator, itis particularly desirable to cause the machine to advance the recordingy medium or tape after the last message character is recorded upon theinstrument so that the en- `tiremessage will-extendbeyond the machine thus I permitting the message to be removed-from the machine and taken-to any retransmitting point Y.

orinstrument or anyV other-.suitable place for editing, storage or other desirable purpose.

=HWever, incase anothermessage-is ldirected to the particular'inachine in question -it is deinterval` of timezaftervr itk has received-.a message or other recognizable or-'idistinguishable `grou oipsignals. n p vAnother object 'of this Ainvention is Atoprovide an arrangement for generating-v '.signals foradvancing the recordingmedium throughs receiving instruments-Which are generallyrecorded in 1 printed form bythe.- usual recordingnand receiving.` instrumentsrempl-oyed in:te1egraph communi- 1 cation networks.

It isv frequently ldesirable to employ recording u. receiving instruments v1infcom'bination .with telep graph switching systems and more 'particularly sirable Ieither to interrupt orf-prevent the ad- -f vancement ofthe recordingA medium or tape f Various arrangements forfaccomplishing some ot these features have been suggested in the past.

These usually require a special transmitter for `automatically transmittingspecial signals upon cessation of the transmission of yregular-or message signals to advance thetape vthrough the -receiving machine or else ythey employ aniodied f 4in :1 combination with.. automatic-- switching sys; tems:

`In-.th is case :itfmay l loe-desirable 'to' have the switching equipment cause the receiving instrument .to .automatically advance a `predetermined@ quantity of record medium outA of the receivingmachine yafter it has received-aimessage or otherv distinguishable groupof signals. HWhen r so'employed it is;desirable'to `stop the automatic `through the mechanism `so that the-'succeeding v `'message will be Iproperly recorded `by the receiving instrument.

operation ofthe machineat as'early a time as `possible when. and if anadditional` message is directed to the receiving equipment.

This invention visiparticularly Well Yadapted and suitable for use f intcombinationwith ya; comprehensive vtelegraphl system :such as :disclosed in patent application of Bacon et al., Serial No.

383,490, filed VMarch 15,1941, or-patentapplical.tionof Krecekyserial No; 408,604,` ledcAugust 28,2'11941, and' also patent application oft Bran- Sonet al., Serial No. 448,87S1ed June 27, 1942,

receiving machine which Will so advance the tape -It is 'an object of thepresent invention to pr'ofunctions described above without 'incorporating f 'f the inherent disadvantages of the previous systems;V For example, the usual recording instru- Y ments may bev employed Which'do not need to be vmodied in any way-to cause them to automati- `cally fadvancel the recording ymedium er tape.

Iny addition, it is not required to utilize Valuable 1 line time for the f transmission of necessary signais to advance the medium through the re- It is-an object of the present invention: to pror'vide an arrangement which will perform the Which patent applications are hereby made a part of this application as if wholly set forth and included herein. Insystem's `oi'this type l thefreceiving equipment at various stations is controlled from anumber of secondaryy switching stations or centers associated'with party line extending to the main switching stationasfset-` forth in` the above-identied. patentl applications. Whenthe invention is incorporated *in*l one or more of the machines 4served by party-lines of systems of this type, which lines also serve other `receiving equipmentat other stations, it-is def sirable to-interrupt the operation of the Yautomatic Irecord advancing circuit and': apparatus during the selection of. any one vofA the stations to insure that thegequipment 'so advancing the Vrecord-medium will be'` idle and available for recording the message should it be the one selected by the selecting equipment. After some other recording instrument has been selected automatic advancement of the record medium through the instrument will be resumed automatically until a desired-quantity of record medium following a message is advanced through the recording equipment. Y

Briey, in accordance with a specific embodiment of this invention, a telegraph reperforator is controlled from a secondary switching unit connected to a p'arty line and an auxiliary control circuit provided adjacent lthe secondary switching unit which will automatically transmit a group of letters signals or some other signals not added to any message for a predetermined interval of time and cause them to be transmitted to the reperforating instrument each time the reperforating instrument is operatively disassociated with or disconnected from the party line. For the purposes of this specification and the claims appended hereto, the terms non-intelligence signals and non-message signals are used to describe and designate any signals or permutation code groups which do not form a part of the subject-matter of messages as recorded by the receiving device at the station of the ultimate destination of the message.

During the time any selecting signals for selecting any of the instruments or equipments associated with the party line are being transmitted thereover, theautomatic generation and transmission of letters signals to the reperforating instrument is interrupted. After the transmission of the selecting signals over the party line, the auxiliary circuit cooperatingwith the secondary' switching centers is either restored, if the associated reperforator has been selected, or else it will resume the generation of letters signals and transmit them tothe reperforator to cause the previously recorded message to be ad vanced out of the mechanism.

At the end of a predetermined minimum interval of time, the equipment at the control center will operate to interrupt the generation of letters signals and restore the circuits to an idle condition. The circuits will then remain in this condition until the reperforator is disconnected from the receiving channel after it has again been selected and recorded another message.

The foregoing objects and features of this invention may be more readily understood from the following description when read with reference to the drawings in which:

Fig, 1 illustrates the manner in which Figs. 2 through 7, inclusive, are positioned adjacent each other to show the details of the circuits equipped and which cooperate in accordance with this invention;

Figs. 2 through 7, inclusive, show details of a typical telegraph system such as disclosed in the above-identified patent application of Branson et al. to which the improved control arrangement for reperforators has been added and incorporated therein.

The details of the specific apparatus and circuit arrangements disclosed in the drawings and described hereinafter are to merely illustrate the manner in which a typical embodiment of this invention is incorporated in a typical telegraph switching system but these details and equipment are not in any Way intended to limit or define the exact scope of this invention as set forth in the claims appended hereto.

As pointed out above, the specific embodiment of the invention described herein and shown in the drawings is adapted to cooperate with the apparatus circuits of the above-identified application of Branson et al.

Figs. 3 and 4 of this application are similar to Figs. 11 and 24 of said Branson et al. application and may be 'directly substituted for these figures providing that the associated additional equip-- ment shown in detail on the right-hand portionl of Fig. 2 is also included with Figs. 3 and 4 of this application. With this addition Figs. 3 and 4 of the present application may be substituted for the corresponding gures in said Branson. application without further change. In this case, however, the equipment and apparatus shown in Figs. 3 and 4, as well as the right-hand portion of Fig. 2, will operate as described herein.

The remaining portion of Fig. 2 as Well as Figs. 5, 6 and 7 show in outline form the various circuits and apparatus comprising a typical switching system such as set forth in the above-identified Branson et al. application.

It is to be understood that the apparatus and circuits in accordance with the present invention for controlling the advancement of the recording medium through a typing reperforator may be applied to any of the other stations or other typing reperforators incorporated in the system either at other stations served by the same party line or by stations served by different party lines. As is understood by those skilled in the art, typing reperforators may be controlled by any of the secondary switching centers and any of the centers may control one or more typing reperforators. In each case, where desired, an arrangement in accordance with the invention may be provided.

Before describing the operation of the improved control arrangement in accordance with this invention, reference will be made to the other equipment of the system which is described in detail in the above-identified Branson et al.

application.

Briefly, the system comprises a plurality of party lines 20| and 580. These party lines comprise a receiving channel 202 and 56|, respectively, for the transmission of signals from a central switching center shown in Figs. 6 and '7 to the respective stations served `by these party lines. The party lines also include a transmission channel 203 and 562, respectively, for the transmission of signals from the outlying stations to the central switching center. As described in the above-identied application of Branson et al., these party lines may be arranged to operate either on a full duplex or half duplex basis. The party line 20| is assumed to be a full duplex party line, while the line 560 is assumed to be a half duplex party line. As will be well understood by those skilled in the art, any number of full duplex and half duplex lines may be provided. As shown in the drawings, full duplex party line 20| extends to the secondary switching centers 215, 3|!! and 5|3. These switching centers con.- trol the stations 215, 211, 218, and 4|9,' the receiving reperforators M5 and 4|0, and stations 52e, 32|, 522, 523 and 524. Party line 560 extends to the secondary control centers 565, 564 and 563, which centers in turn control the stations 566 through 514, inclusive. f

Lines 590 represent a channel extending from switching center shown in Figs. 6 and '7 to a second switching center 593. IThis channel or trunk from the switching center shown in Figs. 6` and 117 .to theisecond'f switching center 593:-.where ref ceivingzequipment 594 .isffassociate'diftherewith. il" The trunk 590 also'l includi-:safsecond.A channel for transmission 'ofsign'alstfrom the sen-dingequipment 595 at the second switchingcenter 593 to r thelcentral exchangeshown in.Fi`gs-.::6f and '7. The` party'z'lines 20114 andl 56B asl well .as the f trunkcircuit 590 may includesany` suitableftype of `telegraph.transrnissionu,fchanneliA As'shown i!" inthe drawings, theselines are fshown as twofoni way ifulll'metallic transmission pathsinan'reffort 'to Vavoid furtherrcomplication'of ther disclosure. It is: to `loef understood, `however,rthat 'these'trans- :..umissionztpaths mayiinclude one lor more of the following types of telegraph 'transmissionvsysteirs and in actual practice:willrfusuallyucomhine a f '.1 number of the dierentrfollowingftypesuof transmission paths. asv will vloe readily understood by 1 those skilled. in the art.v Thetransmissionpaths tof the ldifferentflines. will vary fromsection1t`o section independently of the .type vof transmission I'apparatus'employedi'in any fof the' other'lines 'I or. trunk circuits.

f- L f Brieyy-thesewlines' and channels will include 1 both full andhalf duplex lowrfrequency.telegraph "f l :lines orchannels-which mayribe operated veither on a.- ground.V return rorfullrnetallic basis and of anyoi thewelleknown; composite systems iin- 1 ycluding. simplex. and phantom' circuitsfaswell as so-called Morse legs 'of `cable .quadsai .These chany nels'arnayifalso` includechannelsoi theso-called 'ff `:timeadivision multiplexrtelegraphi systems for the -xtran'smission of signals inneither. one orfifbotli directions.

The telegrapl'iI transmission .channelsmay also include channels ofV voicefrequency carrier telegraphzsystems -as 'well as channelsofyhigh fre- .iquency carrier current telegraph systems and also '1 .f .radio channels. "L These'party .lines will-also.` include the usual :types ofterminal and interconnecting equipment for thezvarious types of communication'systems i employedtlaslwell as the usual-typesioi` amplifiers and repeatersincluding regenerative-repeaters,

andi volume compensator and other control *equipment generally employed with systems of vthe respective types.` -`Inasmuch as the-respective o types of telegraph-systems-operateiintheir usual -imanner'and are well understood by those skilled i. rin the artv they have not been shownlin the draw- J ings huty merely represented by two one-way ftele- .graph channels for each of the lines' of theV sys- 1 if tem.

the central switching station or upon a lcombined feperforator and transmitter 524 comprising reperforating unit 626- and a transmitting unit B25. The transmitter 625 is associated with the director circuit G21 which controls `acrosshar or other type of switch including the selec- "2 tor magnet 628 and the holding magnets T90 and causes the transmitter to be connected=tosome -channel extending towards the party-line for 'f1 which the message is'intended.

As described in the sai-d Branson et al; application," eachl message is preceded byfaplurality As set forth in the alcove-identiledy Branson et al; application, the party lines terminate'at the f f'" 'fcentral'exchange in equipment individual to each The incoming channel party line 7M; terminates in anv incoming line circuit 622. The incoming line circuit causes the message to be recordedteither by receiving-only teletypel Writer 623 when themessages areintended'for :off address characters. .whichcharacters fcontrol the directing. ycircuit 621 and.v causeatransmitter to-befconnected vto tl'1`e.1pr0per.4 channel eX- s-'tendingitoward thestation of address-under con- 5 trol of these address characters. Eachoi the-out- Ii going vlines.isprovided'with one'or more channels offitransmission 1' through the: crossoar' switch.

:=-'I'he'l'party` line 20|. is'providedlwith two" sets of :channels and eachfchannel providedawith a group xoff. relays. individual i 'thereto illustrated vsymbolically at G2G. and 621i; '.Eachof the'. channels is also provided withfa combined. reperforating and ransmzittingA instrument'- 614;' 6 l 5,'1l The :"trans- `inittinglunits lof these"instruments arearranged ;to:ztransmit alternately over theireceiving channel of the :party line 291 and areiprovidedfwith .various .control relays 6H, (SI2i and 6|3: P4 `A transfmitter: start circuit is also asso'ciated'with the far receiving channel or-partyf line 20| for transfrnittingitransmitter. start-signals orzcontrol pat- :;.ter-ns-over this channel?4 These transmitter start patterns :control the switching-equipmentzat the econdary: switching center.` and cause the asso- -i'ciatedz transmitters to bestarted interop-eration #when ithey are'suppliedfwith` stored message -maerial available for transmission. fThe .secondary switching centers" alsorespond orfatleast' certain of thea'ddress :characters and "f :.cause the .receivingequipment controlled by vthem :to -bef selectively and 'operatvelyzconnectednto the receiving channel .of theparty line in accorda ance'withi address characters. sothat thef'respecftive` receiving: equipment will receive themes- '12 sagesv intended forfthem. Theother'party linesof the trunkl circuits are 'ffsimilarly"equipped.. with the vvariouscircuits as .describedabovez iin the: case of thelhalf-duplex .lines only one-'channelthroughv then-crossbar f. switch will generallyzbeprovided since half dup- 40 lex lines: willi-only vheprovidedwhen .trac or ywumessages for the stationsnandl line connected thereto are not heavy:y No transmitter start cir- :l cuit has 'been shown-for the trunk circuitfbecause such: a=circuit generally will be unnecessary-since there will :be .no transmitters `*to loe4 started under :fc-control of thetcentral switching center.' With these exceptions the equipment'providedforeach ofthelinesfand trunksroperate ini substantially f the-same manner and.perform-:substantially the :same-function. f -.Message'x originating-fequipmentr comprising monitoring teletypewriters 'I-'flll,\l:eylooard vperforators 'I i ll :transmitters 'l I 2 control relay -'H 3' and director circuit 'H4 is :provided at the central -switchingstation for the transmission of Ines- 'sages fromthe station lto any of thepther sta- Ationsof the system.

Infaddition; a miscellaneous interceptingl circuit l2-1,l receiving reperforator '126 and tape receptacle Tg5 are provided for the receptiony of irnproperlyl addressed ,messages and other messages :whichfail to lproperly control theswitching equipment. l

A willful'intercept circuit 'i24- andak combined reperforator andtransmitter 120 comprising a reperforator unit ".'2l;andar'transmittingiunit 122 ...-ftogether with'a'.- director circuit 123 arep'rovided for the reception of certain messages intended for 'stations-whichit is desired for one' reason or another.to-interceptV and prevent transmission to ,their.ultimate'station of destination at the particular moment.

;t -The .operation or" the `circuits of such-a typical Aswitching'system has :been-*described in detail '75. .in the above-'identified BransonA etfalcapplication and need not be repeated here. It is to be under- -stood, however, that equipment' and circuits of reperforators are sometimes employed, and prefl erably printing reperforators of the type disclosed in U. S. Patents 2,273,909 and 2,273,910, granted to Swan on February 24, 1942; 2,255,794 granted to Lake on September 16, 1941, all of which patents are hereby made a part of this application as if fully included herein, or of the type described in the above-identiiied Branson et al. application. As described in that application, such a reperforator was shown at or near station 2 9 thereof. In the present application, two such reperforators 4|6 and 4|| are shown at stations 4|5 and 4|0. These stations may be at the same station or place as station 4|9 or they may be at other stations in the same local area as station 4|9. In either event, the printing reperforators 4|6 and 4|| are controlled from the secondary switching center 3|4. In case it is desired to direct a message over some line not a part of the main switching system which terminates at or near station 4|9, the message will be preceded by a particular address code which will cause the message to be directed to one or the other of the printing reperforators. As shown in Fig. 4, messages preceded by'the address code BK will be directed to the printing reperforator 4| 6, while messages preceded by the address code BJ will be directed to the printing reperforator 4| I. Any other suitable code, of course, may be chosen and the switching circuits appropriately connected as described in the above-identified Branson et al. application. However, when the codes rBJ and BK are employed the system will operate without any changes to cause themessages preceded by these codes to be directed to these instruments. The printing and perforating positions in substantially all commercial reperforators and printers are a considerable distance from the edge of the machine. This causes the nal portion of the message to be within the machine when the message is terminated and the machine stopped. In case another message immediately follows the rst message, the end f the rst message will immediately pass out of the machine followed by the second message. However, in case no second message immediately follows the first message, the machine normally will remain at rest until a second message is received. This requires some method of removing the entire first messagefrom the machine in case it is desired to transmit the message over some other circuit prior to the reception of a second message.

In the past it has been customary to manually cause the reperforating machine to advance the record medium and thus the end of the iirst message out of the machine.

This operation of the machine is frequently designated feed-out. Manual operation of the feed-out arrangement interferes with the reception of a succeeding message if it should be received at the time of the manual advancing of the record medium through' the machine. Generally, such manual control of the machine causes at least the first portion of the following message to be mutilated and generally lost. In addition, the manual control of the machine consumes the operators time and requires her attention.

In order to eliminate these undesirable features, an automatic feed-out arrangement is provided in accordance with this invention which will cause the machine to automatically advance the record medium through the machine upon the completion of transmission of a message thereto and which will be interrupted by a succeeding message suiciently early so that the succeeding message will not be in any way altered or mutilated but will be received in its entirety by the receiving reperforator.

Assuming now that the message transmitted over the receiving channel 202 of the party line 20| is intended for the reperforator 4|6. This message will be preceded by the address code BK. In addition, assume that the circuits of the secondary switching center 3|4 are in the position shown in the drawings. They are returned to this position at the end of any previous message transmitted over this system or by the application of power as occurs the rst thing in the morning. The permutation code selector 30| follows all of the signals received over the receiving channel 202 and causes certain of the contacts thereof to be selectively controlled or closed in response to the reception of predetermined signals transmitted over this channel,

The manner in which the selector causes the respective contacts to be closed is described in detail in Patents 2,120,235, granted to Beattie et al. on June 14, 1938; 2,112,234, granted to Beattie et al. on March 29, 1938; and 2,154,547, granted to Walker on April 18, 1939, which patents are hereby made a part of this application as if fully included herein. The selector 30| is provided with the line relay 303 which repeats the signals received over the party line to the control or selector magnet 302 which causes the respective contacts to close in response to the reception of the corresponding signals. In case a message is directed to the station BK the letter B of the address code is absorbed by the switching equipment at the central station so that the first code transmitted over the receiving channel will be the one represented by the letter K.

When this code is received by selector 30| with the circuits in the position shown in the vdrawings, a circuit will be completed for the operation of relay 332 from battery through the Winding of relay 332 and the left-hand inner break contacts of relay 304 to ground through the momentarily operated contacts K of selector 30|. Relay 332 in operating completes the circuit for maintaining itself operated and for operating relay 304. The locking circuit for relay 332 may be traced from the battery through its Winding and lefthand inner operated contacts to ground through the left-hand inner break contacts of relay 331 and the right-hand inner operated contacts of relay 332. The circuit for the operation of relay 304 extends from battery through the winding of relay 304 to ground through the right-hand inner operated contacts of relay 332.

Relay 304 in operating disconnects the circuits through the contacts of the selector 30| so that when these contacts close, due to the reception of the corresponding codes during the transmission of the succeeding message, the switching circuits will not be altered except as described in the above-identified Branson et al. application.

The operation of relay 332 also extends the conta-cts of relay 383 to conductor 460 extending to station 4|5. The succeeding signals transmitted over the party line 20| will then be repeated by relay 383 to the line relay 424 over conductor 460, which relay in turn repeats them to the control magnet 425 of the printing reperforator 4|6. The printing reperforator 4|6 then records the signals of the message. The operation of the circuits for establishing this connection to the reperforator 4| 3 as described above is substantially the same as described in the above-identied application of Branson et al.

When it is desired to control the transmitter associated with the line, the transmission of the message to reperforator 4|6 will be interrupted and later resumed as described in said Branson et al. application without adding any signals to the message, without subtracting any signals from the message, and without mutilating or altering any signals of the message.

The operation of the K contacts of the selector 30|, in response to the code combination representing the letter K preceding the message which is directed to the printing reperforator 4|6, completes a circuit for the operation of relay 250 in addition to completing the circuit for the operation of relay 332, as described above. The circuit for the operation oi' relay 250 may be traced from battery, to the winding of relay 250 to ground through the momentarily operated contacts K of selector 30|. The operation of relay 332y in addition to completing a circuit for maintaining itself operated asdescribed above, also completes the circuit for maintaining relay 250 operated from battery, through the winding of relay 250, the left-hand inner operated contacts of relay 332, the left-hand inner break contacts of relay 331 to ground through the right-hand inner operated contacts of relay 332. The peration of relay 250 connects ground to the lower terminal of condenser 26| and thus completely discharges this condenser. The operation of relay 250 also connects ground to the right-hand terminal and lower winding of relay 253, 'thus maintaining this relay in the position shown in the drawings.

The operation of relay 250 also completes an obvious circuit for the operation of relay 25|. Relay 25| in operating completes a circuit for maintaining itself operated under control of relay 256 from battery through the winding of relay 25|, the left-hand break contacts of relay 25E to ground, through the right-hand inner operated contacts of relay 25|. Thereafter the circuits remain in the condition described during the transmission of the message to the printing reperforator 4| 6 at station 4 l5.

At the conclusion of the message an end-ofmessage signal is transmitted over the receiving channel 232 of party line 20|, as described in detail in the above-identified Branson et al. application. This end-of-message signal comprises a iigures signal, followed by an H signal and the H signal is generally followed by a letters signal to provide suflicient time for the switching circuits to properly function, as described in the above-identicd Branson et al. application.

The FG contacts of the selector 30| close in response to the reception of the gures signal. Closure of these contacts completes the circuit for the operation of relay 345 from battery, through the lower winding of relay 346, through the righthand winding of relay 345, to ground, through the momentarily closed contacts FG.

Relay '345 in operating completes a circuit for maintaining itself operated, from battery, through its left-hand winding, the 1eft-hand outer break contacts of relay 331 and the outer righthand and outer left-hand operated contacts of relay 345, to ground, through the right-hand contact and armature of relay 346. Inasmuch as the upper circuit and the winding oi relay 346.

are not closed until relay 345 operates, at which time current also 'i'l'ows through the lower winding of this relay, relay 346 will remain in the position shown in the drawings. A short interval of time prior to the opening of contacts FG, the UN contacts will open and interrupt the circuit through the upper winding 'of relay 345 so that when the FG contacts open and interrupt the circuit through the lower winding of this circuit, the relay will maintain its armature in the `position show-n and maintain the locking circuit of relay 345 closed.

If the signal following the iigures signal is other than another iigures signal, an H signal, or a blank signal, relay 346 will operate in response thereto and interrupt the locking circuit of relay 345. However, if the succeeding signal is an H signal, the H contacts of selector l30| will be momentarily closed and ccmpletea circuit for the operation of relay 331, from battery, through the lower winding of relay 34B, the winding of 'relay' 331, left-hand inner Aoperated contacts of relay 345, to ground, through the momentarily closed H contacts. A

A short interval of time after the H contacts close,v the UN contacts will close to complete a current is overcome by the effect of the current' flowing through the lower winding of this relay, thus Vmaintaining its armature in the position shown. A short interval of time before the H contacts open, the UN contacts open to interrupt the circuit through the upper winding of this relay before the circuit of the lower winding is in-` terrupted. Thus, this relay will be maintained in the position shown in the drawings.

Relay 331 in operating completes a circuit for maintaining itself operated from battery, through the lower winding of relay 34e, winding and right-hand inner operated contacts of relay 331, the right-hand and left-hand outer operated contacts of relay 345 to ground, through the righthand contact and armature of relay 346. Relay 331 in operating also interrupts the locking circuit of relay 345 which permits this relay to release. The release of relay 345 interrupts the locking circuit of relay 331., which permits this relay to release when the H contacts open after the reception of the H signal.

The operation of relay 331, however, interrupts the locking circuit of both relays 332 and 250 traced above, whereupon both of these relays release prior to the release of relay 331.

The release of relay 332 interrupts the operating circuit' of rel-ay 304. The release of relays 332, 304, s45 and 331 restores the Switching circuits to their normal or idle condition, as set forth lin detail in the above-identified Branson et al. application.

The release of relay 250 completes the circuit for energizing the filament or cathode of tube 251 from ground, throughthe right-hand outer break contacts of relay 250, right-hand outer operated contacts of relay 25|, through resistances 261 and the cathode circuit of tube 251 to battery.

The release of relay 250 also removes ground from the lower terminal of condenser 26|. This terminal of condenser 26| then starts to charge through high resistance 266.

The constants of tube 251 together with the battery potential, resistances 261, condenser 26| and resistance 266 are such that no anode current will flow through tube 251 for some appreciable predetermined interval of time as, for example, fteen seconds.

During this fifteen-second time interval, however, the release of relay 250 connects ground to the armature of relay 254 and to the upper terminal of resistance 264. The circuit from the upper terminal of resistance 264 may be traced through the center left-hand operated contacts of relay 25| and the left-hand inner break contacts of relay 250 to ground. Completion of this circuit causes the armature of relay 254 to operate to its right-hand position due to current flowing from battery through the' upper winding of relay 254, through resistance 264 to ground, through the left-hand contacts of relays 250 and 25| in the circuit described above.

Release of relay 250 also interrupts the circuit in the lower winding of relay 253 and thus permits this relay to operate as described hereinafter.

The operation of relay 254 to its right-hand position due to the current owing in its upper winding as described above connects ground to the right-hand terminals of both its upper and lower windings through its right-hand contact and armature and the center left-hand operated contacts of relay 25| and the left-hand inner break contacts of relay 250. The connection of ground to the right-hand terminal of the upper winding of this relay reverses the flow of current through this winding so that the current now ows through resistance 265 and the upper winding of relay 254 to ground through its right-hand contact and armature in the circuit traced above. The current flowing through its upper winding at this time will thus tend to move the armature of this relay to its left-hand position.

However, it is prevented from doing so at this time due to the fact that condenser 259 discharges through the lower winding of relay 254 in such a direction as totend to maintain its armature in the right-hand position until the discharging current of condenser 259 falls below the value required to maintain the armature of relay 254 in its right-hand position. At this time cunrent flowing through the upper winding of relay 254 will overcome the effect of the current owing through the lower winding of this relay and will cause its armature to move to its left-hand position as shown in the drawings.

When the armature of relay 254 leaves its right-hand contact, ground will be disconnected from the right-hand terminal of the upper and lower windings of this relay and battery will then be connected thereto. Under these conditions current through the upper Winding of this relay will again reverse and tend to move its armature to its right-hand position. At this time, however, it is prevented from doing so due to the charging current of condenser 259 owing through the lower winding of relay 254. At the end of the predetermined interval of time determined by the constants of the relay and circuit of condenser 259. the charging current of condenser 259 will fall to such a value that the armature of relay 254 will again be operated to its right-hand position. Thereafter the above cycle of operation of relay 254 will be repeated and the relay will operate alternately to its right-hand and left-hand positions.

It should be noted that the left-hand terminal of the upper winding of relay 254 is connected to the common point of resistances 264 and 265. Resistances 264 and 265 comprise a potentiometer which causes the current to reverse in the upper winding of relay 254 as described above. By properly choosing the values of resistances 264 and 265 it is possible to control the portion of time the armature rests against each of the contacts since the magnitude of the current owing through the upper winding of this relay need not be the same when the relay is in its two positions. In the preferred embodiment of the invention the values of the resistances and constants of the relay 254 and condenser 259 are so chosen relative to the signaling speed of the system or apparatus that relay 254 will be maintained in its left-hand position only a relatively short interval of time while it will belmaintained in its right-hand position for an interval of time of six and one-half to seven times as long,

' During the time relay 254 is operated to its lefthand position it connects ground to the left termi nal and condenser 260 and thus tends to discharge this condenser. The discharge current of condenser 260 flows through the upper winding of relay 253 in such a direction as to operate relay 253 to its right-hand position where it applies spacing potential to conductor 268 which is connected through the right contacts of relay 332 to the transmission conductor 460 extending to the reperforator 4| 6. A short interval of time later when relay 254 is operated through its righthand position, it interrupts the circuit through its left-hand contacts to the left-hand terminal of condenser 260 whereupon this terminal of condenser 260 starts to charge. The charging current of condenser 260 also flows through the up-' per Winding of relay 253 but in the opposite direction from the discharge current. Consequently the armature of relay 253 is moved to its righthand position where it again applies marking potential to conductor 268 which extends over the line 460 to the reperforator 2 6. Thus, potentials of alternately spacing and marking potential are applied to line 460 extending to the reperforator 4|6.

When the relays operate as indicated above, the spacing potential is applied to the line for a relatively short interval of time which in the preferred embodiment of this invention is approximately equal to the length of the unit impulse of the code employed. Thereafter the marking polarity or the marking condition is applied to the conductor for an interval of time approximately equal to the time required for the transmission of six or six and one-half unit impulses of the code employed. Thus, a spacing condition is transmitted to the reperforator 4|6 for approximately one code interval and then marking potential is applied for six or six and one-half unit intervals of time and then this cycle is repeated. As will be understood by those skilled in the art, the actual lengths of time will vary depending upon the signaling speed of the system or apparatus.

This cycle of impulses when received by the reperforator 4 6 Will be interpreted by it as representing a letters signal. In other words, the spacing impulse will be interpreted as a start signal and the following marking impulses will be interpreted as ve marking impulses followed by a stop impulse of one and one-half or more intervals of time; in this case the system employs the so-called seven and one-half unit code. If the seven-unit code is employed then the interval of time during which marking impulses or signaling conditions are transmitted may be slightly reduced. However, it is desirable to make the marking conditions slightly longer than the minimum length of time required to send the required number of marking impulses to insure that the reperforator M5 will be actually synchronized each time with the signals transmitted.

In other words, relay 254 together with relay 253 operates to generate the series of letters signals which are transmitted to and recorded by the reperforator M6 immediately following the message recorded by this reperforator.

The reperforator responds to these letters signals by punching the tape in accordance with them. However, in the'preferred embodiment of this invention this instrument does not print any character or symbol in response to these signals. However, these instruments may be arranged to print any character or symbol in response to these signals or any other signals Lmay be generated which will cause the printing mechanism to print any desired symbol or character,

The action of the circuits in generating and transmitting letters signals to the reperforator M6 will then continue so long as no signals are receivedA overA the receiving channel 202 of the party line 20! or until the end of the time interval for charging of condenser 26! to a value sufficient to cause anode current to flow through tube 25?.

At the end of this time interval, which may be of the order of fteen seconds, as pointed out above, the lower terminal of condenser 26! will be charged to a suiiiciently positive potential to cause tube 25'] to pass suliicient anode current to operate relay 255. The operation of relay 255 completes an obvious circuit for the operation of relay 255. Relay 256 connects ground to the right-hand terminal of the lower winding of relay 253 and thus maintains the armature of this relay in the position shown in the drawings and interrupts the transmission of letters signals to the reperforatcr M6. The operation of relay 255 also interrupts the locking circuit of relay 25|, which relay releases and deenergizes the filament circuit of tube 250 and thus restores this tube to normal and causes relays 255 and 255 to release. The release of relay 25! also interrupts the circuit to ground from the armature of relay 254 and from resistance 255, thus restoring the circuits of relay 254 to their normal or idle condition.

The circuits will then remain in the idle condition until the message is again directed to the reperforator M6 at which time the operation of the circuits, as described above, will be repeated. During the fifteen-second time interval following above during the reception of the messages bythe for moving the armature of this relay to its 'rightthe transmission of the message to this instrument a series of letters signals will be generated and transmitted to this recording device to advance the end of the message out of the machine so that it may be readily removed in its entirety and taken to some transmitting apparatus or employed in any other desirable manner.

If at any time during this :fifteen-second time interval signals are received over the transmitting channel 202 of party line 200 the transmission of these letters signals will be interrupted. If the succeeding message is intended for reperforator M6 the circuits for generating the letters signals will berestored toy the condition described hand position and also for discharging condenser 258.- This circuit extends from battery through the lower winding of relay 252, contacts of testing jack 263, the left-hand outer operated contacts of relay 25| and the left-hand outer break contacts of relay 250 through the armature and right-hand orspacing Contact of relay 205 to ground through the left outer break contacts of relay 30H.

Relay 205 in following these signalsrtransmitted over the `receiving channel 202 will `cause its armature te be moved to its spacing condition in response to the spacing impulses ofthe signals transmitted over this channel and establish the -circuit described above. During intervals when marking impulses are transmitted over the receiving channel 202 the armature of relay 205 will be operated to its left-hand position where it interrupts the circuit to the lower winding of relay 252, At this time, however, condenser 258 will charge through the lower winding of relay 252 in such a direction as to maintain the armature of relay 252 in its right-hand position and prevent the transmission of letters signals to the reperforator 416. The constants of condenser 258 and relay 252 are such that the armature of relay 252 will be maintained in its right-hand position due to relay 205 responding to the signals transmitted over the receiving channel 202. At the end of these signals condenser 258 starts to charge through the lower winding of relay 252 and after condenser 258 has been charged suinciently, the current, flowing through the lower winding of relay 252 will fall to such a value that current flowing through the upper winding of this relay will move its armature to its left-hand position thus interrupting the circuit through the lower Winding of relay 253 and permitting the transmission of letters signals to be resumed.

If the signals transmittedover the receiving channel during the interval in question cause any other receiving instrument served by the channel to be selected to receive the following messages, relay 304 will operate upon the selection of that instrument and interrupt the circuit to the contacts of relay 205 and the lower winding of relay 252. Upon the charging of the condenser 258,

as described above, the armature of relay 252 vwill be operated to its left-hand position whereupon the transmission of letters signals to the reperforator H6 will be resumed until the end ofthe interval measured by condenserZSl and tube25'l as described above whereupon the circuits will be restored to their normal or idle condition as set forth above.

If Vthe signals received over the channel 202 during the time the letters signals are ybeing transmitted to the reperforator M6 are intended for the reperforatorMG, relay 205- wil-l respond and immediately suspend the transmission of letters signals, and the subsequent operation of relay 332 and relay 250 as described above will establish the connection for the reperforator M6 and restore the circuits of Fig. 2 to the condition described above.

By immediately stopping the automatic transmission of letters signals to the reperforator M6 upon the rst operation of relay 205, as described above, sufficient time is provided before the message is directed to the instrument t insure that this instrument will be at rest when the first signal of the message is transmitted to it and thus insure that the first character of the message will be properly recorded by this instrument;

In case a message is directed to the reperforator 4H the circuits comprising relays 2l0, 2| l, 2|2, 2|3, 2 i4, 2l5, and 2 I6 operate in substantially the same manner as the circuits described above with reference to reperforator 4I6 When messages are directed to both of these'machines due to the operation of relay 348 or a similar relay, letters signals will be transmitted to both of these machines at the end of the message in the same manner as described above.

Similar circuits may be provided at any or all of theother secondary switching centers for controlling any-or all of the recording instruments controlled therefrom, as will be readily understood by those skilled in the art.

While the invention has been embodied in an arrangement suitable for use in a particular switching system, it will be appreciated by those skilled in the art that it may be readily embodied in arrangements suitable for use in other systems.

What is claimed is:

1. In combination, an incoming channel of telegraphic transmission, a reperforator operated under control thereof, a selector separate from the said reperforator associated with said channel, and means under the control of said selector operable responsive to an end-of-message signal for supplying to said reperforator a plurality of non-intelligence code combinations.v

2. In combination, a telegraph transmission channel, transmitting apparatus connected thereto for transmitting messages thereover,` a recording instrument for recording permutation code signals upon a record medium, and apparatus associated with said channel intermediate said message transmitter and said recording instrument for transmitting a plurality of permutation code signals to said recorder which do not form part of any message for causing said recorder to advance the record medium therethrough.

3. In a telegraph system, a channel of telegraphic transmission, a reperforator, a permutation code selector separate from said reperforator connected to said channel for disconnecting said reperforator from said channel under control cf permutation code signals received from said channel, and apparatus operative incident to the disconnection of said reperforator from said channel for transmitting a plurality of predetermined permutation code signals to said reperforator.

4. In a telegraph system, a channel of telegraphic transmission, a reperforator, a permutation code selector separate from said reperforator connected to said channel for disconnecting said reperforator from said channel under control of permutation code signals received over said channel, apparatus operative incident to the disconnection of said reperforator from` said channel (ill for transmitting a' plurality of predetermined permutation code signals to said reperforator, and apparatus responsive a predetermined interval of time after disconnection of said reperforator from said channel for stopping the transmission of said predetermined code combinations.

5. In a telegraphic system, a channel of telegraphic transmission, a reperforator, a permutation code selector separate from said reperforator connected to said channel for disconnecting said reperforator from said channel under control of permutation code signals received from said channel, apparatus operative incident to the disconnection of said reperforator from said channel for transmitting a plurality of predetermined permutation code signals to said reperforator, and apparatus responsive to the transmission of additional signals over said channel for interrupting the transmission of said predetermined character to said reperforator.

6. In a telegraph system, a channel of telegraphic transmission, a plurality of recording instruments, a plurality of permutation code selectors connected to said channel for selectively controlling the operation of said recording instruments in response to permutation code signals received from said channel, apparatus operative following the transmission of a message to one of said recording instruments under control of one of said selectors for transmitting additional permutation code combinations to said recording instrument.

7. In a telegraph system, a channel of telegraphic transmission, a plurality of recording instruments, a plurality of permutation code selectors connected to said channel for selectively controlling the operation of said recording instruments in response to permutation code signals received from said channel, apparatus operative following the transmission of a message to one of said recorders under control of one of said selectors for transmitting non-message permutation code combinations to said recorder, apparatus responsive to further signals transmitted over said channel for interrupting the transmission of said non-message signals to said recorder.

8. In a telegraph system, a channel of telegraphic transmission, a plurality of recording instruments, a plurality of permutation code selectors connected to said channel for selectively controlling the operation of said recording instruments in response to permutation code signals transmitted over said channel, apparatus operative following the transmission of a message to one of said recordersvunder control of one of said selectors for transmitting non-message permutation code combinations to said recorder, apparatus responsive to further signals transmitted over said channel for interrupting the transmission of said non-message signals to said recorder, and apparatus operative incident to `the direction of a message to another recorder for resuming the transmission of said 'non-message signals to said recording device.

9. A telegraph system comprising a plurality of telegraph receiving instruments including a reperforator, a plurality of permutation code selecting instruments, a channel of telegraphic transmission extending to all of said selecting instruments, switching apparatus controlled by said selecting instruments for selectively extending said channel to said receiving instruments, apparatus operating incident to the disconnec- .tion oiA said reperforator from said channel for transmitting a plurality of predetermined permutation code combinations to said reperforator, and apparatus responsive to additional signais transmitted over said channel for interrupting the operation of said apparatus.

10. A .telegraph system comprising a plurality of telegraph receiving instruments including a reperforator, a plurality oi permutation code selecting instruments, a channel of telegraphic transmission extending to all of said selecting instruments, switching apparatus controlled by said selecting instruments for selectively extending said channel to said receiving instruments, apparatus operating incident to the disconnection of said reperiorator from said channel for transmitting a plurality of predetermined permutation code combinations to said reperforator, apparatus responsive to additional signals transmitted over said channel for interrupting the operation of said apparatus, and signal responsive instrumentalities operative incident to the extension of said channel to some other one of said receiving instruments for causing said apparatus `to resume the transmission of said predetermined permutation code combination.

1l, In combination, a telegraph transmission channel, transmission apparatus connected thereto for transmitting telegraph signals thereover, a printing device for yprinting symbols upon a record medium in response yto telegraph signals received over said channel, and apparatus associated with said channel intermediate said message transmitter and said printing device for transmitting a plurality of telegraph signals to said device for causing said printing device to advance the record medium therethrough Without printing any symbols thereupon.

l2. In combination, a telegraph transmission channel, transmission apparatus connected thereto for transmitting telegraph signals thereover, a printing device for printing symbols upon a record medium in response to telegraph signals received over said channel, and apparatus associated with said channel inter-mediate said message transmitter and said printing device for causing said printing device to print symbols on said record medium which do not 'form part of any message for advancing said medium through said printing device.

13. In a telegraph system, achannel of telegraphic transmission, a recording device for recording permutation code signals upon a record medium, and apparatus associated with said channel for generating a lplurality of predetermined signals for causing said recorder to advance the record medium through said recording device, and means controlled solely by predetermined signals received from said charrnel for initiating the operation of said apparatus for generating a plurality of predetermined signals.

WALTER M. BACON. RITA SMITH KINKEAD, Administratri of the Eistctte of Fullerton S. Kinlcead, Deceased. v 

